Payment by a mobile device, such as a mobile phone, personal digital assistant (PDA), and/or the like, is an emerging trend in the retail customer shopping experience. Customers want the ability to use their mobile device as a payment method for retail transactions at a physical point of sale system. Current technologies used to facilitate the interaction of a mobile device with a physical point of sale system include near field communication (NFC) and radio frequency identification (RFID). These current approaches, however, require specific hardware technology to be present in the mobile device and the physical point of sale system. Unfortunatetly, NFC and RFID technologies are available in only a limited number of mobile devices.